Why We Sleep: Science of Sleep & Dreams | Matthew Walker | Talks at Google

Sleep serves as a critical life-support system, essential for cognitive function, emotional stability, and physical health. Chronic sleep deprivation significantly impairs memory consolidation by disrupting hippocampal activity, effectively blocking the brain's ability to encode new information. Beyond cognitive deficits, insufficient sleep compromises the immune system, specifically reducing the activity of natural killer cells, which elevates the risk of various cancers and accelerates tumor growth. Furthermore, sleep loss acts as a physiological stressor that alters gene expression, increases cardiovascular risk, and destabilizes emotional regulation. Evidence from school start time adjustments demonstrates that delaying schedules improves academic performance and reduces accident rates, underscoring the societal importance of adequate rest. Rather than a lifestyle luxury, sleep functions as a vital biological requirement, and its widespread neglect represents a major public health challenge in the 21st century.